A long-standing barrier in optoelectronics has been addressed by researchers at the University of Cambridge's Cavendish Laboratory. 

They have invented a molecular "back door" to power materials previously considered useless for modern electronics.

In particular, the development centers on a technique to electrically power previously insulating nanoparticles, namely lanthanide-doped nanoparticles (LnNPs). 

It has led to the creation of a new class of light-emitting diodes (LEDs) called "LnLEDs," which could advance medical diagnostics, super-fast optical communications, and highly sensitive chemical detectors.

Powering nanoparticles for electronics

LnNP materials are known for their ability to produce incredibly pure and stable light — especially in the second near-infrared (NIR-II) range, which can penetrate biological tissues far deeper than visible light.

The problem? They are electrically insulating. This has prevented the use of these nanoparticles in electronic devices like LEDs. 

"These nanoparticles are fantastic light emitters, but we couldn't power them with electricity. It was a major barrier preventing their use in everyday technology," said Professor Akshay Rao, who led the research at the Cavendish Laboratory. 

The Cambridge team's solution was to create an organic-inorganic hybrid material to circumvent the insulating nature of the LnNPs. 

In this method, an organic dye (9-anthracenecarboxylic acid (9-ACA) is attached to the surface of the LnNPs. This molecule acts as the "antenna."

In the new LnLED design, electrical charges are injected directly into the 9-ACA molecules, bypassing the nanoparticle entirely.

The 9-ACA molecules capture this energy and enter a high-energy triplet excited state (a state often considered "dark" or wasted).

With an efficiency exceeding 98%, energy from the triplet state is transferred to the lanthanide ions in the nanoparticle, resulting in brilliant light emission.